Effects of different inhibitory non-invasive brain stimulation protocols on performance in a motor sequence learning task

Non-invasive brain stimulation technologies (NIBS) are often used to study the functionality of the human motor system. For the aforementioned purpose two protocols are commonly used, namely continuous theta burst stimulation (cTBS) and conventional repetitive transcranial magnetic stimulation (rTMS). The literature shows mixed effects for the inhibitory effects on cortical activity of these different stimulation protocols. The goal of this study was to compare the effects of the two protocols in the same experimental context when the supplementary motor area (SMA) is targeted by the stimulation. In the present study a mixed, single-blinded, sham-controlled research design was used. The experiment took place on two consecutive days. As a behavioral experimental paradigm, the discrete sequence production task (DSP-task) was employed. Based on performance measures during task execution within and between the different experimental groups, the comparison of the protocols was conducted. The results showed inhibitory effects of both stimulation protocols when the stimulation was applied on day one. No effect of the stimulation was revealed when the stimulation was applied on day two. Nevertheless, it was shown that the conventional rTMS protocol had stronger inhibitory effects compared to the cTBS protocol.